Lawn mowers are known having rotary cutting decks attached to or carried by the frame of the mower. Rotary cutting decks carry one or more cutting blades that rotate in substantially horizontal cutting planes. The decks are called rotary decks because of the rotary nature of the blade(s). The grass clippings created by the rotating action of the blade(s) are usually discharged through a discharge opening, often located on the right side of the deck. A discharge chute often extends outwardly from the side of the deck to shield the discharge opening to prevent bystanders from being struck by thrown objects.
Multi-bladed rotary cutting decks of this type are often carried on riding lawn mowers that are operated by an operator who is seated on a seat on the frame of the mower. In addition, rotary cutting decks of this type are also often convertible between a discharge mode of operation, in which the discharge opening is open, and a non-discharge mode of operation, in which the discharge opening is blocked. When the discharge opening is blocked, the grass clippings cannot escape through the discharge opening.
The reason for having a non-discharge mode of operation is to save time when cutting around areas in which the discharge of grass clippings would not be desirable. For example, if the operator is mowing or trimming around flower beds, sidewalks, driveways, or the like, the operator normally wants to prevent grass clippings from being discharged into the flower beds or onto the sidewalks and driveways. In a mower with a continuously open discharge opening oriented on the right side of the mower deck, this meant that the operator always had to place the left or non-discharge side of the cutting deck adjacent the flower beds, sidewalks, driveways, etc. when passing past such areas. Thus, the operator would frequently have to change directions while mowing to get the left side of the cutting deck up against the areas where the clippings should not be discharged. This need to change direction takes extra time and can be annoying to the operator.
Some riding mowers have a blocking member adjacent the discharge opening that comprises a pivotal flap or gate. The gate has a closed position in which the gate covers the discharge opening in the non-discharge mode. The gate also has an open position in which the gate is clear of the discharge opening in the discharge mode.
Thus, when the operator is mowing, if the operator comes to an area where grass clippings should not be discharged and the discharge opening is adjacent such areas, the operator can simply temporarily pivot the gate into its closed position to block the discharge opening. In this position, the grass clippings simply hit the closed gate and fall down to the ground without being discharged outside the deck. When the mower clears this area, the operator can pivot the gate back to its open position to resume discharging grass clippings from the deck. Moving the gate between its open and closed positions can be done quickly and on a temporary basis to block the grass clippings for even very short periods of time without having to change the direction of motion of the mower.
The gate in such mowers is connected by a linkage to an operating handle placed near the operator's seat. The operator can swing the gate between its open and closed positions simply by moving the operating handle from one handle position to another. This can be done without stopping the mower and without the operator dismounting the mower. U.S. Pat. No. 6,874,309 to Bellis, Jr. discloses a handle operated, pivotal gate of this type.
There are disadvantages with hand operated gates of this type. For example, the need to switch modes often occurs when the operator is maneuvering the mower around flower beds or other areas of the like with convoluted, curved borders or side edges. During such maneuvering, the operator would normally prefer to keep both hands on the steering wheel or the steering levers of the mower. But, in order to switch modes of operation, the operator often has to use one hand to move the operating handle to pivot the gate from its open to closed position or vise versa. If the operator wants to switch modes frequently while maneuvering the mower in this manner, the operator has to frequently take one hand off the steering controls in order to do this. This is not desirable.
In addition, in known mowers, the pivotal gate is arranged to be in either an open or closed position. In other words, the handle is moved between two bistable positions in which the handle is locked. In one position of the handle, the gate is held in its open position. In the other position of the handle, the gate is held in its closed position. There is no provision for holding the gate in intermediate position(s) that are partly open/partly closed. This would be a desirable attribute since it would give the operator some means of feathering between the modes of operation if the operator wanted the discharge opening to be partially open and partially blocked at the same time.